Microsprayers for use in irrigation have been known for some time and their increasing use has directed attention to the desirability of reducing the cost of production. In particular, the use of conventional moulding techniques in producing such microsprayers has focused attention on the desirability of producing them with a minimum number of separate components which are then to be assembled. This is particularly the case when it is desired to produce pressure compensating microsprayers whose output remains substantially invariant regardless of pressure variations in the mains input pressure.